The present invention relates generally to vehicles for the handling of material or articles, which are self-loading or unloading and includes successive handling means, and, more particularly, to an interlock selector valve for the hydraulic system of a round bale wagon that is operable to select the operation of the bale handling apparatus and to provide a hydraulic interlock for the operation of the load bed to unload accumulated bales.
The evolution of the hay industry in recent years indicates a diversification in baling, storing and transporting the hay with a strong trend toward using larger bales. Large round bales, varying in weight from about 800 pounds to about 1600 pounds and varying in diameter from about four feet up to about eight feet, are rapidly replacing the relatively smaller conventional square bales.
Due to the large size of the round bales, there is a need for equipment which can pick up the bales in the field, accumulate a load of bales, and transport them to a remote storage area where the accumulated bales can be unloaded. Also, such equipment must be flexible in the ability to deal with bales ranging in diameter from the aforesaid four to eight feet. Furthermore, it is important that the bale handling equipment be able to arrange and control the position of bales on the transporter bed after the bales have been picked up. Transporting larger loads of bales reduces fuel usage and the time required for bale handling.
Currently known round bale handling equipment is limited in being able to successfully pick up, accumulate, transport and unload large loads of round bales, e.g., eight to ten bales, and cope with the varying bale size. Some equipment is available for handling large loads of bales but this equipment is tractor drawn and is thus limited by tractor speed and reduced maneuverability. Other equipment available is self-propelled, such as a pickup truck attachment for handling large round bales. While this other equipment avoids the speed and maneuverability limitations of tractor drawn equipment, it sacrifices the economic advantages associated with transporting a large number of bales.
Since the large round bales present a substantial package of crop material to be handled, it is necessary that the load bed be of rather substantial size. The tilting of the load bed to unload bales therefrom could seriously damage the bale handling and loading mechanisms having significantly less mass and size. Accordingly, it would be desirable that the bale handling mechanisms be in a non-interferring position when the forward end of the load bed is raised to unload the bales.